Sonochemical synthesis of cobalt aluminate nanoparticles under various preparation parameters

Abstract

Cobalt aluminate (CoAl(2)O(4)) nanoparticles were synthesized using a precursor method with the aid of ultrasound irradiation under various preparation parameters. The effects of the preparation parameters, such as the sonochemical reaction time and temperature, precipitation agents, calcination temperature and time on the formation of CoAl(2)O(4) were investigated. The precursor on heating yields nanosized CoAl(2)O(4) particles and both these nanoparticles and the precursor were characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and atomic force microscopy (AFM). The use of ultrasound irradiation during the homogeneous precipitation of the precursor reduces the duration of the precipitation reaction. The mechanism of the formation of cobalt aluminate was investigated by means of Fourier transformation infrared spectroscopy (FT-IR) and EDX (energy dispersive X-ray). The thermal decomposition process and kinetics of the precursor of nanosized CoAl(2)O(4) were investigated by means of differential scanning calorimetry (DSC) and thermogravimetry (TG). The apparent activation energy (E) and the pre-exponential constant (A) were 304.26 kJ/mol and 6.441 x 10(14)s(-1), respectively. Specific surface area was investigated by means of Brunauer Emmett Teller (BET) surface area measurements.

Formation of CoAl2O4 Nanoparticles via Low‐Temperature Solid‐State Reaction of Fine Gibbsite and Cobalt Precursor

“…It is a thermally and chemically stable pigment of intense blue color and is usually synthesized at high temperature by solid-state reaction between two oxide components [1,2]. In the past decades, it has received attention due to its applications as inorganic ceramic blue pigment which is widely used for coloration of plastics, paint, fiber, paper, rubber, phosphor, glass, cement, glazes, ceramic bodies, and porcelain enamels [3][4][5]. Moreover, its unique optical properties lead to its extensive use as color filter for automotive lamps or pigment layer on luminescent materials in optical devices [6][7][8].…”

Effects of starch addition on the characteristics of CoAl2O4 nano pigments

“…, a lower combustion temperature is beneficial to decrease the crystallite sizes of nano metal oxides. On the other hand, at lower temperatures, the partial oxidation of Co 2+ to Co 3+ occurs, and amorphous Co 3 O 4 , which is black in colour, is generated . Therefore, increasing the starch content in the present work (samples c and d) reduced the crystallite size but diminished the lightness of the nano pigments ( L * values in Table ).…”

“…A further novelty of this paper is the lower calcination temperature (600 °C). In a traditional synthesis method, such as a solid‐state reaction , the sol–gel method , and also applying previous fuels in the combustion method , high temperatures (800–1200 °C) are needed to obtain a bright‐blue colour of CoAl 2 O 4 . The effects of starch addition on the physical characteristics (e.g.…”

Simple and Efficient Rout for Synthesis of Spinel Nanopigments

“…Few reports on this topic show that the preparation of same ceramic pigments involves annealing at 1400 ∘ C for 3 h [4]. Even applying new methods such as sonochemical synthesis requires heating treatment at 1000 ∘ C at least for 2 hours for the formation of pure cobalt aluminate spinel phase [18]. Generally, increasing temperature treatment increases the crystallite sizes of powders [19][20][21][22].…”